Technological advances in both electronics and optics pave the way for creating new telecommunications networks that may be structurally and functionally superior to networks based on prior technology. The introduction of a new network to replace an existing network is not, however, an easy task, given the investment made to build the existing network and the risk of deploying untried technology. A tempting approach of incorporating new technology is to consider interposing new advanced network elements in an existing network to accommodate traffic growth. However, the drawback of mingling the old and the new network elements is multifold: (1) such blending would inevitably lead to a complex network having inter-dependent multi-generation components; (2) the interworking of multi-generation components may require complex protocols; (3) flow control and routing may become unwieldy; and (4) new features may be difficult to introduce.
One of the incentives for creating new telecommunication networks is the inadequacy of legacy networks. A glaring example of an inadequate network is the present global data network, the Internet, which evolved rapidly from an experimental network of very limited coverage to a popular network of world-wide coverage. However, the Internet architecture that was intended for limited coverage remained virtually unchanged. The experimental Internet was meant to provide a proof of concept; scalability, service reliability, and service quality were not a concern. Consequently, during its rapid growth, piecemeal measures had to be taken. The adverse result of continuous Internet patching is a complex unmanageable network structure that cannot realize the vision of an omnipresent universal network capable of providing flexible inexpensive broadband services. Such a universal network would spur economic growth and redefine the role that telecommunications can play in the development and welfare of the human society.
Network-element capability dictates the network structure. Technological advances permit the development of powerful new network elements of large dimension, higher speed, better performance, and low cost. Consequently, new network structures can be developed to provide new services with superior performance. Meanwhile, legacy network structures based on prior-art network elements may not be adaptable to benefit from technological advances.
There is a need, therefore, to explore a new means for introducing new network elements and new network structures to avoid undesirable patching and interworking drawbacks.